LOS ANGELES, California (CNN) -- The man who, dressed as Santa Claus, killed nine people at a Christmas Eve party planned to flee to Canada the next day, but California police believe he decided to kill himself instead because of severe burn injuries.

Pardo rigged his rental car so that if someone tried to remove the Santa suit, the car would explode.

During a news conference on Friday, Covina Police Chief Kim Raney said Bruce Jeffrey Pardo had purchased a ticket for an early Christmas Day flight from Los Angeles to Canada.

Raney said that while police do not know why Pardo, 45, decided against his plan to flee, they speculate it may have been due to the burn injuries Pardo received after setting fire to the home where the slayings occurred.

Pardo's body was covered in third-degree burns, Raney said, and part of the Santa suit the gunman wore to the massacre burned and melted into his legs.

Police believe Pardo's injuries came after he set fire to the home using a homemade device used to spread fuel.

Police said that after leaving the home, Pardo changed out of the Santa suit and into regular clothes.

Raney also spoke about a pipe bomb that exploded in Pardo's rental car Thursday night. He said Pardo had rigged the rental car so that if someone tried to remove the Santa suit, the car would explode. The car was packed with ammunition and black powder, he said.

Police said that inside Pardo's home in Montrose, California, they also found five empty boxes for semiautomatic handguns, two high-powered shotguns and "racing fuel," which they believe was used to help set fire to the home.

Police also said they found Pardo's resume, which said he had a bachelor's and master's degree in electrical engineering, but they could not verify if it was accurate. The resume also indicated Pardo had worked in the aerospace field.

Later a voice gasps, "He's left the house -- my mom's house is on fire!"

A distraught woman cries, "My daughter's been shot! She was shot in the face on the side, and she's bleeding!"

Police said Pardo brought four handguns to the home.

The first victim was an 8-year-old girl who ran to the door after hearing a knock, police said. She was shot in the face but survived.

"She has a very, very severe injury to her face. It's not life-threatening, but she's got a very tough road ahead of her," Lt. Pat Buchanan of the Covina Police Department said at a news conference Thursday. Watch police describe girl's injuries »

Raney said Friday that witnesses, who may have caught only glimpses of what was happening because of the chaos, thought Pardo may have targeted some victims. He said witnesses at the party said Pardo may have stood over some of the victims and executed them.

Raney said people at the party were jumping out of windows on both floors of the house trying to escape the gunfire and flames.

"The information we have so far is that Mr. Pardo was married to the daughter of the resident of the house," Raney said. "They'd been married for possibly one year, had recently divorced and a settlement was reached apparently last week. It sounds like that might have been a very contentious divorce."

In addition to the nine people killed, police said three people were injured, including the 8-year-old girl. A 16-year-old girl was wounded by gunfire and was hospitalized with non-life-threatening injuries, police said, and a woman who jumped out of a second-floor window suffered a broken leg and was hospitalized.

Police said they have not accounted for three people: Pardo's ex-mother-in-law, ex-father-in-law and ex-wife.

Pardo's neighbors talked to KABC on Thursday as they watched police search his home.

"He's very nice, very sociable," Cindy Keenan said. She said Pardo always decorated his home for the holidays.

Patrick Guzman said when he encountered Pardo in his yard about two hours before the attack, "He seemed normal."

"He said 'Merry Christmas' to me," Guzman said.

Ed Winter, assistant chief Los Angeles County coroner, said the bodies recovered were "severely burned and charred" and dental and medical records and X-rays will be necessary to establish identities.

Winter said the intense fire caused the top floor of the two-story house to collapse onto the first floor.

Pardo's body was discovered about 30 miles from the shooting scene at his brother's house in the Los Angeles suburb of Sylmar, dead from "a self-inflicted gunshot wound," police said. Relatives returning to the house found Pardo's body, police said.

Buchanan said police received several 911 calls at 8:27 p.m. Wednesday. When officers arrived at the house three to four minutes after the first call, the dwelling was engulfed in flames.

The fire was so intense that firefighters battled the blaze for an hour and a half before knocking the flames down so that officers "were able to look into the house from the outside, and initially saw three bodies in the front portion of the house," he said.

As uninjured people were trying to escape, Buchanan said, "that's when he (Pardo) lit the accelerant in some manner -- we do not know how at this point -- and he fled the scene."

Buchanan said the device that spread accelerant was "nothing that we or the arson-explosives unit has ever seen before. It appears to be homemade."

A Christmas Eve party at the house was a family tradition, Raney said, and the party had often featured a visit from a neighbor who was dressed as Santa Claus. He said that neighbor has moved out of the neighborhood and was not at the party Wednesday night.

Referring to Pardo, Buchanan said, "We don't know at this point whether he was aware that there was a Santa Claus in years past. We're assuming that he did, and that's the reason for the outfit."